The function of an airdam (also referred as a front spoiler) is to reduce the total drag, and to increase volumetric flow of cooling air in a vehicle's engine compartment. As an add-on part, the airdam (usually made of plastic) is placed under the front of the vehicle at nearly a right angle to the flow. The drag reducing effect of an airdam is based on the fact that it diminishes the air speed under a vehicle thus attenuating the contribution of the underbody airflow to the overall drag. This is important since fuel economy is affected by drag. The height of the airdam must be experimentally adjusted for each vehicle model. In most cases the optimum height can not be achieved due to the ground clearance limitations and other road factors (curbside, etc.). It is possible to damage the airdam while driving or parking due to its low clearance. In most cases a damaged airdam must be replaced with a new one.
The prior art includes mechanical aerodynamic control devices. While these prior approaches may reduce drag to some effect, each of the approaches is limited in its effectiveness or desirability. For instance, mechanical aerodynamic control devices add weight and undue complexity to the vehicle. Further, since mechanical controls usually cause drag at off-design conditions, e.g., lower or higher speeds, the mechanical controls desirably must be mechanically adjustable, which further adds to the weight and complexity. And airdams which hang too low hit parking curbs.